Square thumbnail from UIImagePickerViewController image

Question

In my app the user selects an image or take a picture using UIImagePickerViewController. Once the image was selected I want to display its thumbnail on a square UIImageView (90x90). I'm using Apple's code to create a thumbnail. The problem is the thumbnail is not squared, the function, after set kCGImageSourceThumbnailMaxPixelSize key to 90, seems only to resize the image's height, and as far as I know the kCGImageSourceThumbnailMaxPixelSize key should be responsible for setting the height and width of the thumbnail. Here is a glimpse of my code: ``` - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage]; NSData *imageData = UIImageJPEGRepresentation (image, 0.5); // My image view is 90x90 UIImage *thumbImage = MyCreateThumbnailImageFromData(imageData, 90); [myImageView setImage:thumbImage]; if (picker.sourceType == UIImagePickerControllerSourceTypeCa…

Accepted Answer

The easiest thing to do would be to set the `contentMode` on your imageView to be `UIViewContentModeScaleAspectFill` instead. However, this may not be ideal since it would keep the whole image in memory.

Here is some code that I use to resize images.

```
+ (UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)size
{
    UIGraphicsBeginImageContextWithOptions(size, NO, 0);
    [image drawInRect:CGRectMake(0, 0, size.width, size.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    
    UIGraphicsEndImageContext();
    return newImage;
}
```

This version will keep the image from being distorted if the size is not the same aspect ratio as the image.

```
+ (UIImage *)imageWithImage:(UIImage *)image scaledToFillSize:(CGSize)size
{
    CGFloat scale = MAX(size.width/image.size.width, size.height/image.size.height);
    CGFloat width = image.size.width * scale;
    CGFloat height = image.size.height * scale;
    CGRect imageRect = CGRectMake((size.width - width)/2.0f,
                                  (size.height - height)/2.0f,
                                  width,
                                  height);

UIGraphicsBeginImageContextWithOptions(size, NO, 0);
    [image drawInRect:imageRect];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    
    UIGraphicsEndImageContext();
    return newImage;
}
```

Often you want just the top square of an image (rather than the center). And you want the final image to be of a certain size, say 128x128, like in the example below.

```
- (UIImage *)squareAndSmall // as a category (so, 'self' is the input image)
{
    // fromCleverError's original
    // http://stackoverflow.com/questions/17884555
    CGSize finalsize = CGSizeMake(128,128);

CGFloat scale = MAX(
        finalsize.width/self.size.width,
        finalsize.height/self.size.height);
    CGFloat width = self.size.width * scale;
    CGFloat height = self.size.height * scale;

CGRect rr = CGRectMake( 0, 0, width, height);

UIGraphicsBeginImageContextWithOptions(finalsize, NO, 0);
    [self drawInRect:rr];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    
    UIGraphicsEndImageContext();
    return newImage;
}
```

Square thumbnail from UIImagePickerViewController image

Solution

Problem